The project The sustainability of medium-sized language communities in the age of globalization sets out the general lines for a research project that aims to study which social, political and economic factors favour or disfavour the maintenance of middle-sized language communities. The research focuses on those language communities that belong to developed societies in a context of advanced socioeconomic development, in order to see how the globalizing tendency affects medium-sized languages, what this tendency implies and how these language communities face the challenge of staying alive while belonging to the prevailing global context.